Bearing assembly

Abstract

A bearing assembly particularly suitable for the rotor arrangement of an electrical motor or generator includes a bearing located in a housing. The bearing has an inner race, an outer race, and a plurality of ball bearings between the inner and outer races. A portion of the housing is made up of a deformable flexible wall which permits the housing to conform to the shape of the outer race member, rather than forcing the outer race to conform to the shape of the housing, as was experienced hitherto.

1. A bearing assembly comprising:
 a bearing having an inner race and an outer race; 
 a housing for the bearing, wherein a portion of the housing comprises a deformable metallic wall, the deformable metallic wall being configured to deform such that it substantially conforms to a contour of the outer race; and 
 a resilient structure provided on the housing for soft mounting the bearing assembly to a stator. 
 
     
     
       2. A bearing assembly as claimed in  claim 1 , wherein the deformable wall has a thickness of approximately 0.5 mm. 
     
     
       3. A bearing assembly as claimed in  claim 1 , wherein the deformable wall has a thickness of 0.1 mm to 2 mm. 
     
     
       4. A bearing assembly as claimed in  claim 1 ,  2  or  3 , wherein the deformable wall is integral with the rest of the housing. 
     
     
       5. A bearing assembly as claimed in  claim 1 ,  2  or  3 , wherein the deformable wall is in direct contact with the outer race of the bearing. 
     
     
       6. A bearing assembly as claimed in  claim 1 ,  2  or  3 , wherein the housing further comprises an arrangement for supplying lubrication to the bearing. 
     
     
       7. A bearing assembly as claimed in  claim 6 , wherein the arrangement for supplying lubrication comprises a reservoir of fluid. 
     
     
       8. A bearing assembly as claimed in  claim 1 ,  2  or  3 , wherein the housing is thermally conductive. 
     
     
       9. A bearing assembly as claimed in  claim 1 ,  2  or  3 , wherein the deformable wall is manufactured from zinc alloy material. 
     
     
       10. A rotor assembly for a motor comprising a rotor on a shaft having a bearing assembly at each end portion of the rotor assembly as claimed in  claim 1 ,  2  or  3 , the bearings being arranged to rotatably support the rotor and shaft. 
     
     
       11. A rotor assembly as claimed in  claim 10 , further comprising an impeller mounted in fixed relationship on the shaft. 
     
     
       12. A rotor assembly as claimed in  claim 11 , wherein the impeller is located between the bearing assemblies such that, in use, fluid pumped by the impeller is drawn over at least one of the bearing assemblies. 
     
     
       13. A rotor assembly as claimed in  claim 10 , wherein the resilient structure comprises an o-ring substantially concentric with the shaft. 
     
     
       14. A rotor assembly as claimed in  claim 13 , wherein the resilient structure comprises a pair of o-rings substantially concentric with the shaft and arranged at respective end portions of the housing. 
     
     
       15. An electrical machine comprising a rotor assembly as claimed in  claim 13 . 
     
     
       16. An electrical machine as claimed in  claim 15 , further comprising a stator in which the rotor assembly is located, the resilient structures being interposed between the bearing housings and the stator. 
     
     
       17. An electrical machine as claimed in  claim 16 , further comprising a detector detecting the rotational position of the rotor with respect to the stator. 
     
     
       18. An electrical machine as claimed in  claim 17 , further comprising electrical windings on the stator and a controller arranged to energize the windings in dependence on signals from the position detector. 
     
     
       19. An electrical machine as claimed in  claim 18  in the form of a high-speed motor. 
     
     
       20. A cleaning appliance incorporating an electrical machine as claimed in  claim 18 . 
     
     
       21. A cleaning appliance incorporating a rotor assembly as claimed in  claim 13 . 
     
     
       22. A cleaning appliance incorporating a bearing assembly as claimed in  claim 1 ,  2  or  3 . 
     
     
       23. The bearing assembly of  claim 1 , wherein the resilient structure comprises an o-ring.